In general, mixed-signal devices are devices that have both analog and digital components. For example, a mixed-signal device can include both analog and digital circuits integrated into a single semiconductor die. Examples of mixed-signal devices include analog-to-digital converters (ADCs) and digital-to-analog converters (DACs).
One continuing issue in mixed-signal devices is the need for calibration. In mixed-signal devices, calibration can be used to measure and adjust the relationship between analog and digital signals, and thus calibration can be used to improve the accuracy of mixed-signal devices. Unfortunately, current techniques for calibration in mixed-signal devices lack sufficient accuracy for many demanding applications. For example, in mixed-signal devices with high levels of non-linearity, the accuracy of calibration using standard techniques can be insufficient. This can be particularly true for mixed-signal devices where the nonlinearity is poorly characterized, as current techniques for calibration of poorly characterized nonlinearities are particularly problematic. Thus, what are needed are improved devices and techniques for the calibration of mixed-signal devices.